atomicstar
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Engine failure question

Tue May 14, 2019 10:36 pm

Hypothetically, let’s say a 747 encounters an engine failure shortly after reaching cruising altitude. However, it still has over 75 tons of fuel left, and it would be a waste of fuel to dump it to land. Would they try to fly as far as they can? Or would they dump the fuel and try to land at the nearest airport? I know a 747 can ferry flight on 3 engines.

And another question, can a 737 ferry flight on one engine? Hypothetically, a 737 encounters an uncontained engine failure and the exploded fan disc punctures the fuselage (oxygen decompression), and successfully lands at a small airport that normally doesn’t have jets. But they don’t have equipment to replace the engine. Could it take off for a ferry flight to a maintenance facility (let’s say about 250 km away) with only one engine? And especially that a small airport also has a shorter runway.
 
spudsmac
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Re: Engine failure question

Tue May 14, 2019 11:04 pm

atomicstar wrote:
Hypothetically, let’s say a 747 encounters an engine failure shortly after reaching cruising altitude. However, it still has over 75 tons of fuel left, and it would be a waste of fuel to dump it to land. Would they try to fly as far as they can? Or would they dump the fuel and try to land at the nearest airport? I know a 747 can ferry flight on 3 engines.


Yes. Just don't coast out over an ocean or fly over really high terrain in case you lost another engine and the drift-down altitude was higher then the terrain. So don't fly from ANC-ORD but LAX-IAH would be fine.


atomicstar wrote:
And another question, can a 737 ferry flight on one engine? Hypothetically, a 737 encounters an uncontained engine failure and the exploded fan disc punctures the fuselage (oxygen decompression), and successfully lands at a small airport that normally doesn’t have jets. But they don’t have equipment to replace the engine. Could it take off for a ferry flight to a maintenance facility (let’s say about 250 km away) with only one engine? And especially that a small airport also has a shorter runway.


This would not happen as you would not have directional control on the runway. You would have to increase the thrust a little at a time until you got enough air flowing over the rudder to be able to stay straight.
You might be able to do it on a 20,000' runway but the risks would not be worth it. They would just fly the equipment in on another airplane or truck it in.
 
retiredmx
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Re: Engine failure question

Tue May 14, 2019 11:04 pm

when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able. No a 737 is not authorized to perfoem a 1 engine ferry flight.
 
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AirKevin
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Re: Engine failure question

Tue May 14, 2019 11:33 pm

atomicstar wrote:
Hypothetically, let’s say a 747 encounters an engine failure shortly after reaching cruising altitude. However, it still has over 75 tons of fuel left, and it would be a waste of fuel to dump it to land. Would they try to fly as far as they can? Or would they dump the fuel and try to land at the nearest airport? I know a 747 can ferry flight on 3 engines.

retiredmx wrote:
when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able.

British Airways 268 actually did this in 2005. Engine 2 surged shortly after taking off from LAX, and after consulting with dispatch, the flight crew decided to fly as far as they could. They ended up diverting to Manchester over concerns about fuel balance since they weren't able to use the fuel in tank 2. It appears the crew wasn't entirely familiar with how exactly to balance the fuel in a 3-engine situation that they were in. Had they been able to use the fuel in tank 2, they would have actually made it to Heathrow, which was their original destination.

https://assets.publishing.service.gov.u ... _06-06.pdf
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Moose135
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Re: Engine failure question

Tue May 14, 2019 11:46 pm

retiredmx wrote:
when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able.

Tell that to British Airways...
https://en.wikipedia.org/wiki/British_A ... Flight_268
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BoeingGuy
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Re: Engine failure question

Tue May 14, 2019 11:50 pm

Moose135 wrote:
retiredmx wrote:
when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able.

Tell that to British Airways...
https://en.wikipedia.org/wiki/British_A ... Flight_268


He should have specified that applies to a twin-engine airplane. What he said is correct if you are a two engine airplane.
 
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AirKevin
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Re: Engine failure question

Tue May 14, 2019 11:51 pm

Moose135 wrote:
retiredmx wrote:
when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able.

Tell that to British Airways...
https://en.wikipedia.org/wiki/British_A ... Flight_268

Yeah, I just said that.
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fr8mech
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Re: Engine failure question

Wed May 15, 2019 2:59 am

atomicstar wrote:
And another question, can a 737 ferry flight on one engine? Hypothetically, a 737 encounters an uncontained engine failure and the exploded fan disc punctures the fuselage (oxygen decompression), and successfully lands at a small airport that normally doesn’t have jets. But they don’t have equipment to replace the engine. Could it take off for a ferry flight to a maintenance facility (let’s say about 250 km away) with only one engine? And especially that a small airport also has a shorter runway.


I realize this a thought exercise, but quite simply, the operator would truck in everything needed to replace the engine and bring the aircraft back to an airworthy condition. This may include getting a Boeing field service team to assess and repair the aircraft.
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atomicstar
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Re: Engine failure question

Wed May 15, 2019 3:03 am

AirKevin wrote:
It appears the crew wasn't entirely familiar with how exactly to balance the fuel in a 3-engine situation that they were in. Had they been able to use the fuel in tank 2, they would have actually made it to Heathrow, which was their original destination.


Does a 747 have a tank fuel transfer pump (to balance weight in case the two tanks somehow are imbalanced)? If so, was it that the pilots didn’t know how to use it?

retiredmx wrote:
when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able. No a 737 is not authorized to perfoem a 1 engine ferry flight.


If an engine failed but the situation was not critical, I think they would try to land at an airport suitable for a 737 or at least a regional airport (not the best but should land safely) and not a small general aviation airport. But in case of something like a decompression, I think they would try to find any airport (possibly a military airport if needed). And if it is a very critical situation such as a double engine failure, I think they would find anywhere possible to land at (whether it is a field, in water, a highway, etc.). Am I right?
 
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Starlionblue
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Re: Engine failure question

Wed May 15, 2019 3:08 am

atomicstar wrote:
AirKevin wrote:
It appears the crew wasn't entirely familiar with how exactly to balance the fuel in a 3-engine situation that they were in. Had they been able to use the fuel in tank 2, they would have actually made it to Heathrow, which was their original destination.


Does a 747 have a tank fuel transfer pump (to balance weight in case the two tanks somehow are imbalanced)? If so, was it that the pilots didn’t know how to use it


In general, you can't transfer from tank to tank, since most airliners don't have pumps that can transfer from tank to tank*. Crossfeeds allow engines to be fed from the opposite side wing tank in order to balance the fuel as needed. If you got an imbalance due to engine failure, you'd "source" fuel from the engine failure side to decrease the imbalance. If you have a centre tank, you always burn that first, but you could theoretically source the fuel from the wing tanks first but shutting off the centre tank fuel pumps.

* The A330/A340 has trim tank transfers to and from the wing tanks, but that has nothing to do with engine feed.

Image
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RetiredWeasel
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Re: Engine failure question

Wed May 15, 2019 3:31 am

The BA incident has been discussed in nausea on this board during the past 15 years. While I make no judgments, I can tell you that the 747 CPTs in the US airlines wouldn't have continued the route had an engine failed shortly after starting the leg. In fact the Captains I was flying with at the time on the 744 on red tails called the decision 'stupid' or worse. Even the FAA got into the act and tried to admonish the crew, but the UK agency disagreed and defended the pilots and basically told the FAA to FxxxOff. During my tenure there was more than one 747 that returned to NRT due to engine problems (not fire) instead of proceeding to MSP or DTW
Last edited by RetiredWeasel on Wed May 15, 2019 3:40 am, edited 1 time in total.
 
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7BOEING7
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Re: Engine failure question

Wed May 15, 2019 3:33 am

atomicstar wrote:

If an engine failed but the situation was not critical, I think they would try to land at an airport suitable for a 737 or at least a regional airport (not the best but should land safely) and not a small general aviation airport. But in case of something like a decompression, I think they would try to find any airport (possibly a military airport if needed). And if it is a very critical situation such as a double engine failure, I think they would find anywhere possible to land at (whether it is a field, in water, a highway, etc.). Am I right?


With a decompression they may well continue to their destination (fuel permitting) at 10,000 feet, don't need to land ASAP

Suitable is the key word -- it gets defined many different ways.
 
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AirKevin
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Re: Engine failure question

Wed May 15, 2019 5:13 am

atomicstar wrote:
AirKevin wrote:
It appears the crew wasn't entirely familiar with how exactly to balance the fuel in a 3-engine situation that they were in. Had they been able to use the fuel in tank 2, they would have actually made it to Heathrow, which was their original destination.

Does a 747 have a tank fuel transfer pump (to balance weight in case the two tanks somehow are imbalanced)? If so, was it that the pilots didn’t know how to use it?

Negative. The only way to do it would be by having the crossfeeds turned on and shutting off the fuel pumps to the tanks you don't want to use. The problem in this instance according to the AAIB report was the operator's fuel balancing procedures were different from that of the manufacturer. They were using the override pumps to balance the fuel instead of the main pumps. Once the fuel gets to a low enough level, the override pumps aren't really effective, which resulted in the problems they had.
atomicstar wrote:
retiredmx wrote:
when you lose an engine you are required to land at the nearest suitable airport, dump fuel to get below max landing wt if able. No a 737 is not authorized to perfoem a 1 engine ferry flight.

If an engine failed but the situation was not critical, I think they would try to land at an airport suitable for a 737 or at least a regional airport (not the best but should land safely) and not a small general aviation airport. But in case of something like a decompression, I think they would try to find any airport (possibly a military airport if needed). And if it is a very critical situation such as a double engine failure, I think they would find anywhere possible to land at (whether it is a field, in water, a highway, etc.). Am I right?

The key word here being suitable. You'd have to go into your ops specs to see which airport would be suitable for the aircraft you're flying and go from there. As for a decompression, once you drop down to 10,000 feet, you're at an altitude with breathable air, at which point the passengers can take their oxygen masks off. Should you choose to divert, you'd still go for a suitable airport, not just any airport, since you're not really in any immediate danger once you're down to 10,000 feet. If you have a double engine failure, you don't really have too many options at that point since the only way you're going is down. The few double engine failures I can think of off the top of my head are Air Canada 143, Air Transat 236, Ethiopian 961, Taca 110, and US Air 1549. The first three happened at altitudes high enough that they were able to try to go for an airport. Air Canada 143 ended up where they thought was an airport, but unbeknownst to them, it had been converted into a drag strip. Air Transat 236 actually did make it to an airport. Taca 110 was at a low enough altitude that they weren't able to make it to the destination airport, and they ended up landing on a levee. In all three instances, the aircraft was repaired and returned to service. Ethiopian 961 would have made it to an airport, but a last-minute fight with the hijackers caused the Captain to lose visual reference of the airport, and he ended up ditching instead. As for US Air 1549, they lost both engines shortly after take-off, so they weren't able to make it to any airport (there were several nearby), and they ended up in the Hudson River. So if you're at a high enough altitude, you could potentially make it to an airport, depending on where you are. At a lower altitude, not really so much.
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Starlionblue
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Re: Engine failure question

Wed May 15, 2019 5:46 am

7BOEING7 wrote:
atomicstar wrote:

If an engine failed but the situation was not critical, I think they would try to land at an airport suitable for a 737 or at least a regional airport (not the best but should land safely) and not a small general aviation airport. But in case of something like a decompression, I think they would try to find any airport (possibly a military airport if needed). And if it is a very critical situation such as a double engine failure, I think they would find anywhere possible to land at (whether it is a field, in water, a highway, etc.). Am I right?


With a decompression they may well continue to their destination (fuel permitting) at 10,000 feet, don't need to land ASAP

Suitable is the key word -- it gets defined many different ways.


Indeed. Different abnormal situations require different decisions. You don't want to go to a "black hole" airport on a small island with barely and fire and rescue support if it would mean more risk than continuing.

In our manual airports have three "suitability definitions", in increasing order of desirability:
- Adequate - Can you physically land the aircraft there, taking into account things like runway length, fire and rescue, and pavement strength?
- Suitable - Is the airport adequate as per above, plus are the environmental conditions fine for landing?
- Available - Is the airport available for landings, including lighting, ATC, navaids and so on?
(- Online port - While not part of the three definitions, for non-urgent situations ops would much prefer you go to an online port than some random location where there is no contracted support staff and so on.)

If you have an uncontrollable fire, go for the nearest adequate airport. If you have a medical emergency or an engine failure but the situation is relatively stable, consider the nearest suitable airport. If the situations is not urgent, e.g. you've decompressed but are stable at 10000 feet and no one needs urgent medical attention, by all means continue to the nearest available airport.

All situation dependent on the day.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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dennypayne
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Re: Engine failure question

Wed May 15, 2019 4:53 pm

AirKevin wrote:
If you have a double engine failure, you don't really have too many options at that point since the only way you're going is down. The few double engine failures I can think of off the top of my head are Air Canada 143, Air Transat 236, Ethiopian 961, Taca 110, and US Air 1549.


Southern 242 is on that list as well. They probably could have made it to an airport initially, but by the time they gave up on restarts, they were too low and ended up landing on a highway, with pretty disastrous results.
A300/310/319/320/321/332/333/343/380 AN24/28/38/148 ATR72 B190
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Woodreau
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Re: Engine failure question

Wed May 15, 2019 8:57 pm

Same for Pinnacle. Flamed out both engines at 410 didn’t let anyone know about it being a dual engine flame out until it was below 13000 - they had been trying just to get any engine going all the way down and flew past several airports before they ran out of altitude.
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Re: Engine failure question

Wed May 15, 2019 10:50 pm

I'll add British Airways 38 to the list. Although not a total engine failure, both engines did lose thrust when they were at an altitude of 720 feet, just 2 miles away from runway 27L. Obviously, they didn't have too many choices as to where they could put the plane down since they were already on final approach at a low altitude, and the only way the plane was going was down. As the First Officer was the one flying, the Captain decided to let him handle the landing. He also decided to bring the flaps from 30 up to 25. The plane touched down 890 feet short of the runway.
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BoeingGuy
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Re: Engine failure question

Thu May 16, 2019 5:57 am

AirKevin wrote:
I'll add British Airways 38 to the list. Although not a total engine failure, both engines did lose thrust when they were at an altitude of 720 feet, just 2 miles away from runway 27L. Obviously, they didn't have too many choices as to where they could put the plane down since they were already on final approach at a low altitude, and the only way the plane was going was down. As the First Officer was the one flying, the Captain decided to let him handle the landing. He also decided to bring the flaps from 30 up to 25. The plane touched down 890 feet short of the runway.


Actually he brought the flaps to 20, as I understand it. Brilliant move that saved a lot of lives.
 
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AirKevin
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Re: Engine failure question

Thu May 16, 2019 11:19 am

BoeingGuy wrote:
AirKevin wrote:
I'll add British Airways 38 to the list. Although not a total engine failure, both engines did lose thrust when they were at an altitude of 720 feet, just 2 miles away from runway 27L. Obviously, they didn't have too many choices as to where they could put the plane down since they were already on final approach at a low altitude, and the only way the plane was going was down. As the First Officer was the one flying, the Captain decided to let him handle the landing. He also decided to bring the flaps from 30 up to 25. The plane touched down 890 feet short of the runway.

Actually he brought the flaps to 20, as I understand it. Brilliant move that saved a lot of lives.

Not from what I've read, but in any case, better than nothing.
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Horstroad
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Re: Engine failure question

Thu May 16, 2019 7:41 pm

Starlionblue wrote:
In general, you can't transfer from tank to tank, since most airliners don't have pumps that can transfer from tank to tank

Not particularly on-topic... but as you brought it up...

On the MD11 you can transfer fuel from one tank to the other even in flight and it's actually normal procedure. The aircraft does it automatically. The schedule is tail tank and lower aux tank to upper aux tank, upper aux tank to main tank 2, main tank 2 to main tanks 1 and 3, main tanks to engine.
All Pumps in the aux tanks and tail tank* feed directly in the fill/crossfeed manifold. Also each main tank has a transfer pump that feeds directly in the fill/crossfeed manifold (one of the exceptions you mentioned with "most airliners" I guess). You can also use any boost pump for fuel transfer when you open the corresponding crossfeed valve.
You just pressurize the fill/crossfeed manifold from any source you like and open any fill valve to transfer fuel... with a few rules. In flight the tail and lower aux tanks can only transfer to the upper aux tank and the upper aux tank and main tanks can only transfer to the main tanks (in manual mode). On ground you can transfer from/to anywhere without leaving the cockpit just using the MCDU which is very convenient.

*except for the tail alternate pump, which feeds directly to eng #2 in case fuel can't be transferred from the tail tank forward, to keep the aircraft within C/G limits.

Image
 
BravoOne
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Re: Engine failure question

Thu May 16, 2019 8:57 pm

On ground you can transfer from/to anywhere without leaving the cockpit just using the MCDU which is very convenient."

I have never heard of this feature in spite of flying the MD11 for about 7 years. Is this an aproved flight crew procedure, or one of this closely guarded secrets that maintenance uses? I realize that being on the ground would imply that maybe it does not fall into the realm of a flight crew procedure. Interesting, none the less. More than one crew has flamed out the #2 engine by mishandling the fuel system while it was in a manual mode.
 
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Horstroad
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Re: Engine failure question

Thu May 16, 2019 10:21 pm

BravoOne wrote:
On ground you can transfer from/to anywhere without leaving the cockpit just using the MCDU which is very convenient."

Is this an aproved flight crew procedure, or one of this closely guarded secrets that maintenance uses?


It's a maintenance thing... but not a secret :D
Enter the CFDS -> LRU maintenance -> FSC and perform a return to service test. Now you have control over every pump and valve, even the ones not accessible via the overhead panel, like the aux fill isolation valve and the tail fill isolation valve.
But when the automatic fuel schedule doesn't work, you'd call for maintenance anyways. So I guess flight crews wouldn't use it even if they knew the option.
I don't know if you are "allowed" to enter the CFDS at all. At my operater we got the flight crew to the point where some of them can clear an EPGS fault message without calling us. But that's all they ever do with the CFDS.
 
BravoOne
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Re: Engine failure question

Thu May 16, 2019 11:18 pm

Horstroad wrote:
BravoOne wrote:
On ground you can transfer from/to anywhere without leaving the cockpit just using the MCDU which is very convenient."

Is this an aproved flight crew procedure, or one of this closely guarded secrets that maintenance uses?


It's a maintenance thing... but not a secret :D
Enter the CFDS -> LRU maintenance -> FSC and perform a return to service test. Now you have control over every pump and valve, even the ones not accessible via the overhead panel, like the aux fill isolation valve and the tail fill isolation valve.
But when the automatic fuel schedule doesn't work, you'd call for maintenance anyways. So I guess flight crews wouldn't use it even if they knew the option.
I don't know if you are "allowed" to enter the CFDS at all. At my operater we got the flight crew to the point where some of them can clear an EPGS fault message without calling us. But that's all they ever do with the CFDS.



Thanks, way beyond my pay grade!
 
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Starlionblue
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Re: Engine failure question

Fri May 17, 2019 3:06 am

Horstroad wrote:
Starlionblue wrote:
In general, you can't transfer from tank to tank, since most airliners don't have pumps that can transfer from tank to tank

Not particularly on-topic... but as you brought it up...

On the MD11 you can transfer fuel from one tank to the other even in flight and it's actually normal procedure. The aircraft does it automatically. The schedule is tail tank and lower aux tank to upper aux tank, upper aux tank to main tank 2, main tank 2 to main tanks 1 and 3, main tanks to engine.
All Pumps in the aux tanks and tail tank* feed directly in the fill/crossfeed manifold. Also each main tank has a transfer pump that feeds directly in the fill/crossfeed manifold (one of the exceptions you mentioned with "most airliners" I guess). You can also use any boost pump for fuel transfer when you open the corresponding crossfeed valve.
You just pressurize the fill/crossfeed manifold from any source you like and open any fill valve to transfer fuel... with a few rules. In flight the tail and lower aux tanks can only transfer to the upper aux tank and the upper aux tank and main tanks can only transfer to the main tanks (in manual mode). On ground you can transfer from/to anywhere without leaving the cockpit just using the MCDU which is very convenient.

*except for the tail alternate pump, which feeds directly to eng #2 in case fuel can't be transferred from the tail tank forward, to keep the aircraft within C/G limits.

Image


Now that's something I never thought I'd see. An airliner with fuel system more convoluted than the A330s. :D

"The fuel system in the A330 was obviously designed by a lunatic" - Technical school instructor.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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Horstroad
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Re: Engine failure question

Fri May 17, 2019 8:51 pm

Starlionblue wrote:
Now that's something I never thought I'd see. An airliner with fuel system more convoluted than the A330s. :D

"The fuel system in the A330 was obviously designed by a lunatic" - Technical school instructor.

If this stuff turns you on, you can click on the image to see the complete schematic. In this simplified schematic that I showed here, I edited all the float valves and -switches and sense lines out to make it somewhat presentable.

The A380 fuel system is even more complex. Unfortunately I don't have a schematic on hand, but I've seen it the other day and it's just insane. The same lunatic obviously still works for airbus and has improved his game :D
 
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Starlionblue
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Re: Engine failure question

Fri May 17, 2019 11:11 pm

Horstroad wrote:
Starlionblue wrote:
Now that's something I never thought I'd see. An airliner with fuel system more convoluted than the A330s. :D

"The fuel system in the A330 was obviously designed by a lunatic" - Technical school instructor.

If this stuff turns you on, you can click on the image to see the complete schematic. In this simplified schematic that I showed here, I edited all the float valves and -switches and sense lines out to make it somewhat presentable.

The A380 fuel system is even more complex. Unfortunately I don't have a schematic on hand, but I've seen it the other day and it's just insane. The same lunatic obviously still works for airbus and has improved his game :D


Yeah, I saw an A380 diagram a while ago. Trim tank like on the A330, three tanks per wing, and a feed tank for each engine.

Image
Image

They seemingly came to their senses and didn't let him touch the A350. As simple and straightforward a fuel system as one could ask for.

Image
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
snasteve
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Re: Engine failure question

Sat May 18, 2019 12:20 am

RetiredWeasel wrote:
The BA incident has been discussed in nausea on this board during the past 15 years. While I make no judgments, I can tell you that the 747 CPTs in the US airlines wouldn't have continued the route had an engine failed shortly after starting the leg. In fact the Captains I was flying with at the time on the 744 on red tails called the decision 'stupid' or worse. Even the FAA got into the act and tried to admonish the crew, but the UK agency disagreed and defended the pilots and basically told the FAA to FxxxOff. During my tenure there was more than one 747 that returned to NRT due to engine problems (not fire) instead of proceeding to MSP or DTW


Of course the US airlines would not have continued on the route, that would take them away from their homebase and repair facilities. In BAs case, they were flying home where repairs were easiest.
 
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Re: Engine failure question

Sat May 18, 2019 2:18 am

snasteve wrote:
RetiredWeasel wrote:
The BA incident has been discussed in nausea on this board during the past 15 years. While I make no judgments, I can tell you that the 747 CPTs in the US airlines wouldn't have continued the route had an engine failed shortly after starting the leg. In fact the Captains I was flying with at the time on the 744 on red tails called the decision 'stupid' or worse. Even the FAA got into the act and tried to admonish the crew, but the UK agency disagreed and defended the pilots and basically told the FAA to FxxxOff. During my tenure there was more than one 747 that returned to NRT due to engine problems (not fire) instead of proceeding to MSP or DTW


Of course the US airlines would not have continued on the route, that would take them away from their homebase and repair facilities. In BAs case, they were flying home where repairs were easiest.


You’re missing the point. The point is whether the BA decision to continue was safe. As pointed out a US crew returned to Japan rather than continuing to their home base.

You don’t continue to where repairs are easiest if it’s not a prudent safe choice. Question is whether continuing over water with one engine failed on a 4-engine plane is unsafe or not?
 
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Re: Engine failure question

Sat May 18, 2019 2:19 am

Starlionblue wrote:
Horstroad wrote:
Starlionblue wrote:
Now that's something I never thought I'd see. An airliner with fuel system more convoluted than the A330s. :D

"The fuel system in the A330 was obviously designed by a lunatic" - Technical school instructor.

If this stuff turns you on, you can click on the image to see the complete schematic. In this simplified schematic that I showed here, I edited all the float valves and -switches and sense lines out to make it somewhat presentable.

The A380 fuel system is even more complex. Unfortunately I don't have a schematic on hand, but I've seen it the other day and it's just insane. The same lunatic obviously still works for airbus and has improved his game :D


Yeah, I saw an A380 diagram a while ago. Trim tank like on the A330, three tanks per wing, and a feed tank for each engine.

Image
Image

They seemingly came to their senses and didn't let him touch the A350. As simple and straightforward a fuel system as one could ask for.

Image


Geezus, who in the world designed that A380 complexity?
 
atomicstar
Topic Author
Posts: 52
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Re: Engine failure question

Sat May 18, 2019 2:45 am

BoeingGuy wrote:
You’re missing the point. The point is whether the BA decision to continue was safe. As pointed out a US crew returned to Japan rather than continuing to their home base.

You don’t continue to where repairs are easiest if it’s not a prudent safe choice. Question is whether continuing over water with one engine failed on a 4-engine plane is unsafe or not?


I don’t really know much about the technical workings of aircraft. What really are the issues that would occur from flying on 3 engines? Other than possible fuel imbalance issues and possibility of another engine failing (likely not going to happen, and in this case, a 747 would very likely would be able to land). I know that by FAA and many other administrations, they would definitely say a plane with a failed engine would need to land regardless of how much fuel is left in the tank, and regardless of if repairing there is easy.
 
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Starlionblue
Posts: 19170
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Re: Engine failure question

Sat May 18, 2019 3:00 am

BoeingGuy wrote:
Starlionblue wrote:
Horstroad wrote:
If this stuff turns you on, you can click on the image to see the complete schematic. In this simplified schematic that I showed here, I edited all the float valves and -switches and sense lines out to make it somewhat presentable.

The A380 fuel system is even more complex. Unfortunately I don't have a schematic on hand, but I've seen it the other day and it's just insane. The same lunatic obviously still works for airbus and has improved his game :D


Yeah, I saw an A380 diagram a while ago. Trim tank like on the A330, three tanks per wing, and a feed tank for each engine.

Image
Image

They seemingly came to their senses and didn't let him touch the A350. As simple and straightforward a fuel system as one could ask for.

Image


Geezus, who in the world designed that A380 complexity?


The same lunatic who did the A330 saw his chance to really leave his mark. :D

I think they need three main tanks per wing to manage bending moment. Burn the fuel in the inners first. Why they need one feed tank per engine beats me. The A388 doesn't even have the center tank that was going to go in the A389 and the A388F.

The trim tank, while adding a layer, does make the aircraft much more efficient. By transferring fuel back during the cruise, the CG is moved back, decreasing fuel burn. Same as on A330/A340.

On the A350, the trim tank was done away with. Instead, the flaps partially extend during the cruise to move the center of lift forward, essentially achieving the same effect as moving the CG back.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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zeke
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Re: Engine failure question

Sat May 18, 2019 3:01 am

snasteve wrote:
Of course the US airlines would not have continued on the route, that would take them away from their homebase and repair facilities. In BAs case, they were flying home where repairs were easiest.


An engine failure on a quad is not necessarily an emergency, in this BAs case it was not. Therefore fuel dumping or an overweight landing could not be defend.

I don’t think the availability of maintenance facilities would have been a consideration. Being lighter, better stopping performance, crew familiarity, better go around performance, no enroute 2 engine performance issues would have been my considerations.

BoeingGuy wrote:
You don’t continue to where repairs are easiest if it’s not a prudent safe choice. Question is whether continuing over water with one engine failed on a 4-engine plane is unsafe or not?


I would have no difficulty on flight over water, the concern for me would be flight over high terrain. With an engine shutdown the considerations are what happens if another engine were to fail. Then terrain clearance is an issue, or not an issue if over water.

The rules for continued flight with one engine shutdown comes from the super constellation days when engines are were far less reliable.

BoeingGuy wrote:
Geezus, who in the world designed that A380 complexity?


The complexity is driven by regulation for rotor burst, the A340 and 747 are also complex. The QF32 incident demonstrated that the regulations were well founded.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
KAUSpilot
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Re: Engine failure question

Sat May 18, 2019 3:05 am

The philosophy on the course of action to take after an engine failure in a 747 seems to vary from airline to airline. At my previous job it was generally accepted that you will probably not continue if you are more than a few hours away from your destination (divert to kef or snn if on the NAT, maybe CTS on the NOPAC, etc). You aren't going to go the extreme of taking it into shemya or the azores unless you're on fire or lose 2 engines.

At other operators, it seems the philosophy is to continue to destination unless there was a fire or severe damage. There is a performance penalty for flying with 3 engines, so the range of the airplane and 2 engine drift down performance in that configuration must be considered. I don't necessarily agree with that philosophy, but if you did something like jettison 100,000 pounds of fuel prior to an air turn-back simply because you had to shut one down due to compressor stalls etc, then it might not end well for you if your employer has their way. I think they would strongly prefer you to at least move the jet closer to destination, even if not all the way there, than jettison fuel for an immediate ATB. Of course I fly freight not pax, so considerations are different.
Last edited by KAUSpilot on Sat May 18, 2019 3:07 am, edited 1 time in total.
 
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zeke
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Re: Engine failure question

Sat May 18, 2019 3:06 am

atomicstar wrote:
I know that by FAA and many other administrations, they would definitely say a plane with a failed engine would need to land regardless of how much fuel is left in the tank, and regardless of if repairing there is easy.


Flight beyond the nearest suitable airport is permitted by the FAA and most other regulators on a quad with an engine shutdown. The manufacturer actually supplies performance data for that.

When empty the of passengers and freight, quads are actually allowed to takeoff on 3 engines and ferry to a maintenance base.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
BoeingGuy
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Re: Engine failure question

Sat May 18, 2019 3:44 am

zeke wrote:
atomicstar wrote:
I know that by FAA and many other administrations, they would definitely say a plane with a failed engine would need to land regardless of how much fuel is left in the tank, and regardless of if repairing there is easy.


Flight beyond the nearest suitable airport is permitted by the FAA and most other regulators on a quad with an engine shutdown. The manufacturer actually supplies performance data for that.

When empty the of passengers and freight, quads are actually allowed to takeoff on 3 engines and ferry to a maintenance base.


Right. I read that the 707 could continue to its destination if two engines fail. We know the BA event was not afoul of a regulation. The question for you guys is, is it good judgement to continue over an ETOPS segment if 1/4 engines fail on a quad? Is it smart practice?
 
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Starlionblue
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Re: Engine failure question

Sat May 18, 2019 3:45 am

BoeingGuy wrote:
zeke wrote:
atomicstar wrote:
I know that by FAA and many other administrations, they would definitely say a plane with a failed engine would need to land regardless of how much fuel is left in the tank, and regardless of if repairing there is easy.


Flight beyond the nearest suitable airport is permitted by the FAA and most other regulators on a quad with an engine shutdown. The manufacturer actually supplies performance data for that.

When empty the of passengers and freight, quads are actually allowed to takeoff on 3 engines and ferry to a maintenance base.


Right. I read that the 707 could continue to its destination if two engines fail. We know the BA event was not afoul of a regulation. The question for you guys is, is it good judgement to continue over an ETOPS segment if 1/4 engines fail on a quad? Is it smart practice?


I suppose it depends on why it failed exactly.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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7BOEING7
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Re: Engine failure question

Sat May 18, 2019 3:56 am

zeke wrote:

When empty the of passengers and freight, quads are actually allowed to takeoff on 3 engines and ferry to a maintenance base.


If certified to do so. In previous discussions of 3 engine ferry I believe it was mentioned that the 748 was not certified for 3 engine ferry — I could be mistaken.

Boeing used to provide 3 engine ferry services (2 engine on the 727) to various airlines that had contracted with them. In the mid to early 80’s this was discontinued due to insurance issues and the inability to keep crews qualified — you just don’t take a couple of pilots off the line and say “go for it “.
 
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zeke
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Re: Engine failure question

Sat May 18, 2019 4:34 am

7BOEING7 wrote:
If certified to do so. In previous discussions of 3 engine ferry I believe it was mentioned that the 748 was not certified for 3 engine ferry — I could be mistaken.

Boeing used to provide 3 engine ferry services (2 engine on the 727) to various airlines that had contracted with them. In the mid to early 80’s this was discontinued due to insurance issues and the inability to keep crews qualified — you just don’t take a couple of pilots off the line and say “go for it “.


I would have to look at the manuals to see if it is still available on the 748, it is available on the 744. We have an internal training package that needs to be completed before doing a 3 engine ferry, it involves a specific simulator profile. It is not random line pilots doing the job. 3 engine ferry is still an attractive process as not every airport has main deck loaders.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
Max Q
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Re: Engine failure question

Sat May 18, 2019 12:29 pm

A 747 with one engine shutdown still has more redundancy remaining than a 757 or 767 with all engines operating
The best contribution to safety is a competent Pilot.
 
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zeke
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Re: Engine failure question

Sat May 18, 2019 12:31 pm

With the exception of being able to start the APU.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
BravoOne
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Re: Engine failure question

Sat May 18, 2019 1:52 pm

Most flight Tris and Quad oceanic/remote flight plans are built around the loss of two engines, not just one. More than once I have seen UAL 747's going from NRT to SFO and continuing on after the loss of one engine. Mind you, this was not a fire but either cautionary shutdown of other type of flameout. Performance degradation seems to be minimal ofnthe 747 with 1EO. Probably a lot safer than a night time diversion into King Salmon or Petro.
 
BoeingGuy
Posts: 6037
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Re: Engine failure question

Sat May 18, 2019 9:49 pm

BravoOne wrote:
Most flight Tris and Quad oceanic/remote flight plans are built around the loss of two engines, not just one. More than once I have seen UAL 747's going from NRT to SFO and continuing on after the loss of one engine. Mind you, this was not a fire but either cautionary shutdown of other type of flameout. Performance degradation seems to be minimal ofnthe 747 with 1EO. Probably a lot safer than a night time diversion into King Salmon or Petro.


I had heard that landing at your destination airport is statistically safer than a diversion. That had been discussed during some procedure development at the manufacturer I work for. You don’t want to give guidance to divert if you don’t have to. Besides economic impact and passenger convenience, you don’t want someone landing at Barrow at night in a 30 knot crosswind and snowstorm if it weren’t absolutely necessary.
 
atomicstar
Topic Author
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Re: Engine failure question

Sun May 19, 2019 1:12 am

BoeingGuy wrote:
Right. I read that the 707 could continue to its destination if two engines fail. We know the BA event was not afoul of a regulation. The question for you guys is, is it good judgement to continue over an ETOPS segment if 1/4 engines fail on a quad? Is it smart practice?


Same with a 747, it can also fly on 2 engines for emergency landing only. It can produce enough speed to regain altitude. This is what happened on BA flight 9, where all 4 engines stopped as it sucked in volcanic ash. They were able to get one engine running, which slowed the descent while gliding. Then a second one running, and began to regain altitude. At the end, they emergency landed with 3 engines.
 
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Erebus
Posts: 946
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Re: Engine failure question

Sun May 19, 2019 2:05 am

LH once crossed the Atlantic to their intended destination with an A346 on 3 engines after shutting down No.2 near Canada.

viewtopic.php?t=770113

(Edit: Just noticed that the above linked thread has airlines and airports displaying the names when hovering over the abbreviations. How is it not possible now on these newer threads?? :irked: )
 
BravoOne
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Re: Engine failure question

Mon May 20, 2019 2:02 pm

The 707 was a real handful if you had two engines out on the same side. It was a part of every FAA rating ride, and recurrent check thereafter just as a single engine approach to landing was in the 727, DC10, L1011 and MD11. The good news is that I don't recall other than once, having to shut down an engine on the 707.
 
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zeke
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Re: Engine failure question

Tue May 21, 2019 6:18 am

atomicstar wrote:

Same with a 747, it can also fly on 2 engines for emergency landing only. It can produce enough speed to regain altitude. This is what happened on BA flight 9, where all 4 engines stopped as it sucked in volcanic ash. They were able to get one engine running, which slowed the descent while gliding. Then a second one running, and began to regain altitude. At the end, they emergency landed with 3 engines.


The A340 could actually fly and even climb on one engine, at light weights. The APU on the A340 could be started whilst airborne unlike the 747 classic and 744.

Speeds for approach were higher, and there was no going around as the gear was dropped by gravity.

Two engine out approaches were easier to handle on the A340 compared to the 747.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
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Boair
Posts: 110
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Re: Engine failure question

Tue May 21, 2019 8:09 am

Corsair did it a few times.
747-400 departing La Reunion, birdstrike on one engine so they had to shut it down during climb. Rather than turning back, they decided to continue to Paris Orly (12 hours of flight). I remember hearing liveatc and the ATC reaction when he asked the pilots if they had been flying from La Reunion on 3 engine :D
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